Python socket.IP_MULTICAST_LOOP Examples

def _create_ipv4_sockets(loopback_enabled):
    # Open a multicast send socket, with IP_MULTICAST_LOOP enabled or disabled as requested.
    mcast_address = "224.0.1.195"
    port = 49501
    group = (mcast_address, port)
    txsock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    txsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    if loopback_enabled:
        txsock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 1)
    else:
        txsock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 0)
    txsock.connect(group)
    # Open a multicast receive socket and join the group
    rxsock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    req = struct.pack("=4sl", socket.inet_aton(mcast_address), socket.INADDR_ANY)
    rxsock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, req)
    rxsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    rxsock.bind(group)
    return (txsock, rxsock) 

def _create_ipv6_sockets(loopback_enabled):
    # Open a multicast send socket, with IP_MULTICAST_LOOP enabled or disabled as requested.
    intf_name = find_ethernet_interface()
    intf_index = socket.if_nametoindex(intf_name)
    mcast_address = "ff02::abcd:99"
    port = 30000
    group = (mcast_address, port)
    txsock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    txsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    txsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_IF, intf_index)
    if loopback_enabled:
        txsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 1)
    else:
        txsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 0)
    txsock.connect(group)
    # Open a multicast receive socket and join the group
    rxsock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    req = struct.pack("=16si", socket.inet_pton(socket.AF_INET6, mcast_address), intf_index)
    if platform.system() == "Darwin":
        rxsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, req)
    else:
        rxsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_ADD_MEMBERSHIP, req)
    rxsock.bind(("::", port))
    return (txsock, rxsock) 

def _init_advertiser(self):
        sock = _find_sock()
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, struct.pack('@I', 1))
        sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, struct.pack('@I', 1))
        if sock.family == socket.AF_INET6:
            sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, struct.pack('@I', 1))
        sock.bind(('', self.port))

        addrs = _resolve_addrs(self.addresses, None, self.ignore_unavailable, (sock.family,))

        for fam,to,orig_fam,orig_addr in addrs:
            try:
                _multicast_join_group(sock, orig_fam, orig_addr)
            except socket.error:
                if not self.ignore_unavailable:
                    raise

        self._sock = sock 

def init_v4(self):
        idx = socket.if_nametoindex(self.interface.name)
        self.multicast_address = (WSD_MCAST_GRP_V4, WSD_UDP_PORT)

        # v4: member_request (ip_mreqn) = { multicast_addr, intf_addr, idx }
        mreq = (
            socket.inet_pton(self.family, WSD_MCAST_GRP_V4) +
            socket.inet_pton(self.family, self.address) +
            struct.pack('@I', idx))
        self.recv_socket.setsockopt(
            socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)

        try:
            self.recv_socket.bind((WSD_MCAST_GRP_V4, WSD_UDP_PORT))
        except OSError:
            self.recv_socket.bind(('', WSD_UDP_PORT))

        self.send_socket.setsockopt(
            socket.IPPROTO_IP, socket.IP_MULTICAST_IF, mreq)
        self.send_socket.setsockopt(
            socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 0)
        self.send_socket.setsockopt(
            socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, args.hoplimit)

        self.listen_address = (self.address, WSD_HTTP_PORT) 

def create_socket(self, channels, ttl, multicast_loop, broadcast, source_address=None):
        "Create a UDP multicast socket"
        self.sock = socket.socket(socket.AF_INET,
                                  socket.SOCK_DGRAM,
                                  socket.IPPROTO_UDP)
        self.sock.setsockopt(socket.IPPROTO_IP,
                             socket.IP_MULTICAST_TTL,
                             ttl)

        for address, port in channels:
            if source_address and ipaddress.IPv4Address(address).is_multicast:
                try:
                    self.sock.setsockopt(socket.SOL_IP,
                                         socket.IP_MULTICAST_IF,
                                         socket.inet_aton(source_address))
                    print("added membership, interface source address: %s, group: %s" % (source_address, address))
                    self.sock.setsockopt(socket.SOL_IP,
                                         socket.IP_ADD_MEMBERSHIP,
                                         socket.inet_aton(address) + socket.inet_aton(source_address))
                except:
                    print("failed to add membership, interface source address: %s, group: %s. This is ok for unicast." % (source_address, address))

        if multicast_loop is True:
            self.sock.setsockopt(socket.IPPROTO_IP,
                                 socket.IP_MULTICAST_LOOP, 1)

        if broadcast is True:
            self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

        self.destinations = [
            (address, port)
            for address, port in channels
        ]

        IP_PMTUDISC_DO = 2
        IP_MTU_DISCOVER = 10

        # Set DF flag on IP packet (Don't Fragment) - fragmenting would be bad idea
        # it's way better to chunk the packets right.
        self.sock.setsockopt(socket.IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DO) 

def _loopback_needed(ipv6):
    # If we receive a single copy when loopback is disabled, then we need to disable loopback
    if _copies_received(ipv6, False) == 1:
        return False
    # We receive zero copies with loopback disabled. Make sure we do receive a single copy with
    # loopback enabled.
    copies = _copies_received(ipv6, True)
    if copies == 1:
        return True
    elif copies == 0:
        assert False, "We don't receive multicast packet with or without IP_MULTICAST_LOOP"
    else:
        assert False, "Unexpected IP_MULTICAST_LOOP behavior"
    return False  # To make Pylint happy 

def new_socket():
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    # SO_REUSEADDR should be equivalent to SO_REUSEPORT for
    # multicast UDP sockets (p 731, "TCP/IP Illustrated,
    # Volume 2"), but some BSD-derived systems require
    # SO_REUSEPORT to be specified explicity.  Also, not all
    # versions of Python have SO_REUSEPORT available.
    # Catch OSError and socket.error for kernel versions <3.9 because lacking
    # SO_REUSEPORT support.
    try:
        reuseport = socket.SO_REUSEPORT
    except AttributeError:
        pass
    else:
        try:
            s.setsockopt(socket.SOL_SOCKET, reuseport, 1)
        except (OSError, socket.error) as err:
            # OSError on python 3, socket.error on python 2
            if not err.errno == errno.ENOPROTOOPT:
                raise

    # OpenBSD needs the ttl and loop values for the IP_MULTICAST_TTL and
    # IP_MULTICAST_LOOP socket options as an unsigned char.
    ttl = struct.pack(b'B', 255)
    s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
    loop = struct.pack(b'B', 1)
    s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, loop)

    s.bind(('', _MDNS_PORT))
    return s 

def new_socket():
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    # SO_REUSEADDR should be equivalent to SO_REUSEPORT for
    # multicast UDP sockets (p 731, "TCP/IP Illustrated,
    # Volume 2"), but some BSD-derived systems require
    # SO_REUSEPORT to be specified explicity.  Also, not all
    # versions of Python have SO_REUSEPORT available.
    # Catch OSError and socket.error for kernel versions <3.9 because lacking
    # SO_REUSEPORT support.
    try:
        reuseport = socket.SO_REUSEPORT
    except AttributeError:
        pass
    else:
        try:
            s.setsockopt(socket.SOL_SOCKET, reuseport, 1)
        except (OSError, socket.error) as err:
            # OSError on python 3, socket.error on python 2
            if not err.errno == errno.ENOPROTOOPT:
                raise

    # OpenBSD needs the ttl and loop values for the IP_MULTICAST_TTL and
    # IP_MULTICAST_LOOP socket options as an unsigned char.
    ttl = struct.pack(b'B', 255)
    s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
    loop = struct.pack(b'B', 1)
    s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, loop)

    s.bind(('', _MDNS_PORT))
    return s 

def setLoopbackMode(self, mode):
        mode = struct.pack("b", operator.truth(mode))
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, mode) 

def getLoopbackMode(self):
        return self.socket.getsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP) 

def setLoopbackMode(self, mode):
        mode = struct.pack("b", operator.truth(mode))
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, mode) 

def getLoopbackMode(self):
        return self.socket.getsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP) 

def setLoopbackMode(self, mode):
        mode = struct.pack("b", operator.truth(mode))
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP,
                               mode) 

def getLoopbackMode(self):
        return self.socket.getsockopt(socket.IPPROTO_IP,
                                      socket.IP_MULTICAST_LOOP) 

def set_loopback_mode(self, mode):
        mode = struct.pack("b", operator.truth(mode))
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP,
                               mode) 

def _server_discovery(self):
        MULTI_GROUP = ("<broadcast>", 7359)
        MESSAGE = b"who is JellyfinServer?"

        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        sock.settimeout(1.0)  # This controls the socket.timeout exception

        sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 20)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
        sock.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_LOOP, 1)
        sock.setsockopt(socket.IPPROTO_IP, socket.SO_REUSEADDR, 1)

        LOG.debug("MultiGroup      : %s", str(MULTI_GROUP))
        LOG.debug("Sending UDP Data: %s", MESSAGE)

        servers = []

        try:
            sock.sendto(MESSAGE, MULTI_GROUP)
        except Exception as error:
            LOG.exception(traceback.format_exc())
            LOG.exception(error)
            return servers

        while True:
            try:
                data, addr = sock.recvfrom(1024)  # buffer size
                servers.append(json.loads(data))

            except socket.timeout:
                LOG.info("Found Servers: %s", servers)
                return servers

            except Exception as e:
                LOG.error(traceback.format_exc())
                LOG.exception("Error trying to find servers: %s", e)
                return servers 

def create_multicast_sock(own_ip, remote_addr, bind_to_multicast_addr):
        """Create UDP multicast socket."""
        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock.setblocking(False)

        sock.setsockopt(
            socket.SOL_IP,
            socket.IP_MULTICAST_IF,
            socket.inet_aton(own_ip))
        sock.setsockopt(
            socket.SOL_IP,
            socket.IP_ADD_MEMBERSHIP,
            socket.inet_aton(remote_addr[0]) +
            socket.inet_aton(own_ip))
        sock.setsockopt(
            socket.IPPROTO_IP,
            socket.IP_MULTICAST_TTL, 2)
        sock.setsockopt(
            socket.IPPROTO_IP,
            socket.IP_MULTICAST_IF,
            socket.inet_aton(own_ip))

        # I have no idea why we have to use different bind calls here
        # - bind() with multicast addr does not work with gateway search requests
        #   on some machines. It only works if called with own ip. It also doesn't
        #   work on Mac OS.
        # - bind() with own_ip does not work with ROUTING_INDICATIONS on Gira
        #   knx router - for an unknown reason.
        if bind_to_multicast_addr:
            if platform == "win32":
                sock.bind(('', remote_addr[1]))
            else:
                sock.bind((remote_addr[0], remote_addr[1]))
        else:
            sock.bind((own_ip, 0))
        sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 0)
        return sock 

def setLoopbackMode(self, mode):
        mode = struct.pack("b", operator.truth(mode))
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, mode) 

def getLoopbackMode(self):
        return self.socket.getsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP) 

def setLoopbackMode(self, mode):
        mode = struct.pack("b", operator.truth(mode))
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP,
                               mode) 

def getLoopbackMode(self):
        return self.socket.getsockopt(socket.IPPROTO_IP,
                                      socket.IP_MULTICAST_LOOP) 

def setLoopbackMode(self, mode):
        mode = struct.pack("b", operator.truth(mode))
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, mode) 

def getLoopbackMode(self):
        return self.socket.getsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP) 

def setLoopbackMode(self, mode):
        mode = struct.pack("b", operator.truth(mode))
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP,
                               mode) 

def getLoopbackMode(self):
        return self.socket.getsockopt(socket.IPPROTO_IP,
                                      socket.IP_MULTICAST_LOOP) 

def receiver(service='mihome'):
    from plugins import gateway

    assert service in MULTICAST, 'No such service'
    store = get_store()
    address, port = MULTICAST.get(service)
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.bind(("0.0.0.0", port))
 
    mreq = struct.pack("=4sl", socket.inet_aton(address), socket.INADDR_ANY)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 32)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 1)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, SOCKET_BUFSIZE)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
    sock.settimeout(20)  # 2x of heartbeat period

    current = {}

    while True:
        try:
            data, _ = sock.recvfrom(SOCKET_BUFSIZE)  # buffer size is 1024 bytes
        except socket.timeout:
            continue
        print(datetime.now().isoformat(), data)
        if service == 'mihome':
            message = json.loads(data.decode())
            data = json.loads(message['data'])
            if message.get('model') in ('sensor_ht', 'weather.v1') and not sensor_ht.process(conn, cursor, current, message, data):
                continue
            elif message.get('model') == 'magnet':
                magnet.process(store, message, data)
            elif message.get('model') == 'gateway':
                gateway.process(store, message, data)
            current = {}
        elif service == 'yeelight':
            yeelight.process(data.decode()) 

def _server_discovery(self):
        
        MULTI_GROUP = ("<broadcast>", 7359)
        MESSAGE = "who is EmbyServer?"
        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        sock.settimeout(1.0) # This controls the socket.timeout exception
        sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 20)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
        sock.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_LOOP, 1)
        sock.setsockopt(socket.IPPROTO_IP, socket.SO_REUSEADDR, 1)
        
        LOG.debug("MultiGroup      : %s", str(MULTI_GROUP))
        LOG.debug("Sending UDP Data: %s", MESSAGE)
        servers = []

        try:
            sock.sendto(MESSAGE, MULTI_GROUP)
        except Exception as error:
            LOG.error(error)

            return servers

        while True:
            try:
                data, addr = sock.recvfrom(1024) # buffer size
                servers.append(json.loads(data))
            
            except socket.timeout:
                LOG.info("Found Servers: %s", servers)

                return servers
            
            except Exception as e:
                LOG.error("Error trying to find servers: %s", e)

                return servers 

def create_socket_ipv4_tx_mcast(self, multicast_address, port, loopback):
        try:
            sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
        except IOError as err:
            self.warning("Could not create IPv4 UDP socket: %s", err)
            return None
        self.enable_addr_and_port_reuse(sock)
        if self._ipv4_address is not None:
            try:
                sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_IF,
                                socket.inet_aton(self._ipv4_address))
            except IOError as err:
                self.warning("Could not set IPv6 multicast interface address %s: %s",
                             self._ipv4_address, err)
                return None
        try:
            loop_value = 1 if loopback else 0
            sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, loop_value)
        except IOError as err:
            self.warning("Could not set IPv4 multicast loopback value %d: %s", loop_value, err)
            return None
        try:
            sock.connect((multicast_address, port))
        except IOError as err:
            self.warning("Could not connect UDP socket to address %s port %d: %s",
                         multicast_address, port, err)
            return None
        return sock 

def new_socket(interface_number=None, interface_name=None):
    """
    Create a new socket for a given interface_number. 
    interface_name and interface_number have to be for the same interface 

    """
    #Default is IPv4
    address_family = socket.AF_INET

    intf = None #The interface used to transmit data

    if interface_number is None: 
        #No ipv6 interface given. Stay in ipv4 
        intf = socket.gethostbyname(socket.gethostname())
    else: #IPv6 
        intf = int(interface_number)
        address_family = socket.AF_INET6

    #Create socket 
    s = socket.socket(address_family, socket.SOCK_DGRAM)

    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    # SO_REUSEADDR should be equivalent to SO_REUSEPORT for
    # multicast UDP sockets (p 731, "TCP/IP Illustrated,
    # Volume 2"), but some BSD-derived systems require
    # SO_REUSEPORT to be specified explicity.  Also, not all
    # versions of Python have SO_REUSEPORT available.
    # Catch OSError and socket.error for kernel versions <3.9 because lacking
    # SO_REUSEPORT support.
    try:
        reuseport = socket.SO_REUSEPORT
    except AttributeError:
        pass
    else:
        try:
            s.setsockopt(socket.SOL_SOCKET, reuseport, 1)
        except (OSError, socket.error) as err:
            # OSError on python 3, socket.error on python 2
            if not err.errno == errno.ENOPROTOOPT:
                raise


    # OpenBSD needs the ttl and loop values for the IP_MULTICAST_TTL and
    # IP_MULTICAST_LOOP socket options as an unsigned char.
    if address_family is socket.AF_INET: 
        ttl = struct.pack(b'B', 255)
        s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
        loop = struct.pack(b'B', 1)
        s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, loop)
    
    else: #IPv6
        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, 255)
        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 1)

    if interface_name is "awdl0" and platform.system() == 'Darwin':
        s.setsockopt(socket.SOL_SOCKET, 0x1104, 1)

    #Bind the Socket
    s.bind(('', _MDNS_PORT))
    return s 

def new_socket(interface_number=None, interface_name=None):
    """
    Create a new socket for a given interface_number. 
    interface_name and interface_number have to be for the same interface 

    """
    #Default is IPv4
    address_family = socket.AF_INET

    intf = None #The interface used to transmit data

    if interface_number is None: 
        #No ipv6 interface given. Stay in ipv4 
        intf = socket.gethostbyname(socket.gethostname())
    else: #IPv6 
        intf = int(interface_number)
        address_family = socket.AF_INET6

    #Create socket 
    s = socket.socket(address_family, socket.SOCK_DGRAM)

    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    # SO_REUSEADDR should be equivalent to SO_REUSEPORT for
    # multicast UDP sockets (p 731, "TCP/IP Illustrated,
    # Volume 2"), but some BSD-derived systems require
    # SO_REUSEPORT to be specified explicity.  Also, not all
    # versions of Python have SO_REUSEPORT available.
    # Catch OSError and socket.error for kernel versions <3.9 because lacking
    # SO_REUSEPORT support.
    try:
        reuseport = socket.SO_REUSEPORT
    except AttributeError:
        pass
    else:
        try:
            s.setsockopt(socket.SOL_SOCKET, reuseport, 1)
        except (OSError, socket.error) as err:
            # OSError on python 3, socket.error on python 2
            if not err.errno == errno.ENOPROTOOPT:
                raise


    # OpenBSD needs the ttl and loop values for the IP_MULTICAST_TTL and
    # IP_MULTICAST_LOOP socket options as an unsigned char.
    if address_family is socket.AF_INET: 
        ttl = struct.pack(b'B', 255)
        s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
        loop = struct.pack(b'B', 1)
        s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, loop)
    
    else: #IPv6
        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, 255)
        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 1)

    if interface_name is "awdl0" and platform.system() == 'Darwin':
        s.setsockopt(socket.SOL_SOCKET, 0x1104, 1)

    #Bind the Socket
    s.bind(('', _MDNS_PORT))
    return s